Troubleshoot 03 Cummins

[5S Cattle]

Borrowed my truck to a guy that works for my dad while his truck was in the shop. He brought it back and said it was getting hard to start. Well, now it won't start. But I rolled it down a hill and dumped the clutch in 4th and it started right up and has/will if it has been running that day. You let it sit over night and it won't start by turning the key. Have to push start. Any ideas?

 

[callmefence]

Battery,cables starter
Will it jump
Will it crank by jumping the starter.

 

[5S Cattle]

Battery,cables starter
Will it jump
Will it crank by jumping the starter.

Never tried any of that because it turns over fine. Figured it was a fuel issue?

 

[callmefence]

Battery,cables starter
Will it jump
Will it crank by jumping the starter.

Never tried any of that because it turns over fine. Figured it was a fuel issue?

Well now we know.

I'd still wager its a battery/starter issue.
Just turning over isn't enough for a diesel. It's gotta crank fast enough. Will it fire on ether?

 

[5S Cattle]

Battery,cables starter
Will it jump
Will it crank by jumping the starter.

Never tried any of that because it turns over fine. Figured it was a fuel issue?

Well now we know.

I'd still wager its a battery/starter issue.
Just turning over isn't enough for a diesel. It's gotta crank fast enough. Will it fire on ether?

Cranks like it normally would when I turn the key. Just won't start. We soaked a rag with some gas and it did start up on the fumes when he brought it back. I haven't tried that again.

 

[jltrent]

Has the lift pump or injector pump ever been replaced? A lot of the times the lift pump will get weak and take the injection pump out also. IF it turns over ok then either a filter, bad fuel, pumps or injectors? The rolling off part is what don't make sense and as said before the starter isn't turning fast enough to crank. Is the starter engaging?

I bet a weak lift pump...not building the pressure it should.

 

[Atimm693]

I would first make sure the lift pump is working. You should be able to loosen the fuel filter or crack the feed line on the injection pump, turn the key on, and see if it's pumping.

A lot of times they will run without a lift pump. Not very well and they're usually hard to start, and it can cause damage to the injection pump.

 

[Silver]

I'd be curious to see if the fuel shut off is opening when cranking. Battery might just be weak enough to not hold it open while cranking, but strong enough to open it for a bomb start.

Edit: I just got to thinking that your engine probable doesn't have a shut off solenoid, probably an actuator run by the ecm, so it could be an ecm problem.

 

[callmefence]

It could be a variety of issues caused by low voltage during cranking. After the truck starts and the battery s get a charge it does ok right. ?
Try leaving a automatic charger on it overnight..see what happens.

I chased a almost identical problem in a 05. We cussed it every morning for days.
Ended up being a bad battery :bang:

 

[5S Cattle]

I'll test the batteries tomorrow. Could be the culprit. They ain't exactly new. So I'm the lift pump deal, all I have to do is pop the top open on the filter and see if it's pumping I'm there?

 

[Atimm693]

I'll test the batteries tomorrow. Could be the culprit. They ain't exactly new. So I'm the lift pump deal, all I have to do is pop the top open on the filter and see if it's pumping I'm there?

Yeah, open the bleeder if it has one. An 04 should have an electric pump in the tank. You may need to crank the engine or jumper the relay to make the pump run.